Timing on Geithner successor is key

White House chief of staff Jacob "Jack" Lew (seen here with Tim Geithner) is said to be in the short list of contenders for the next Treasury Secretary. However, timing is key.

It's long been expected that Treasury Secretary Tim Geithner would stay on long enough in the job to play a key role in the fiscal cliff negotiations. Now that the deal is done, observers say the White House has a small window to name a successor.

Geithner is expected to stay on until the end of this month.

"Secretary Geithner has previously stated that he plans to be at Treasury until around the inauguration," said a Treasury spokesperson.

The White House is in a tough spot over the timing, with another contentious debate over raising the debt ceiling just weeks away and fiscal cliff negotiations only half done.

"Since we're going right into the debt ceiling debate, it does complicate matters," said Brian Gardner, a senior vice president and Washington analyst for Keefe, Bruyette & Woods.

As part of the fiscal cliff deal, Congress pushed back severe cuts to the federal budget by two months. The budget cuts, which had been scheduled to kick in Jan. 2, are expected to lead to job losses and furloughs for federal employees. The next Treasury secretary would play a role in blunting those cuts.